[Vor. 1 
14 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
Summarizing the data for the rates in table rr, day intervals, 
we find that Q:Q', in the successive periods, as .86:1.14, as 
1.28:2.2, as 1.28:3.46, and as .93:1.7. If we make the ratio 
before spraying equal in each case, to 1.0, then the value for 
the periods after spraying in the successive day intervals are 
respectively 1.33, 1.72, and 1.83. These differences in rate 
are so marked and consistent as to outweigh all considerations 
of individual differences, as disclosed by a detailed study of 
the figures in table п. It will also be noted that the less 
extensive data from table r are confirmatory; thus 0:0” 
in the successive intervals, as .75:.97, as.75:1.41, and as .75:2.3. 
On the basis of 1.0 for the ratio before spraying, we have for 
the periods after spraying, respectively, 1.29, 1.88, and 3.07. 
From the records of the potometer experiments it is obvious 
that only one conclusion may be drawn, namely, that the rate 
of transpiration is materially increased after spraying. 
Some points relative to environmental conditions, however, 
require special mention, and certain suggestive results must 
be left for further experimental study. Attention has been 
drawn to the fact that, in general, the potometer experiments 
were conducted in the open, during early October. During 
the last days of the work, cooler weather and danger from 
rain made it desirable to transfer the potometers to а room in 
the building, and the data for the third and fourth days after 
spraying, table п, were secured under these new conditions. 
In this room the shades were drawn and every precaution 
taken to secure uniformity. It will be noted that while the 
order of results is in the same direction as for the lawn exposure, 
the ratio is even higher than the average. No “shading action" 
of the Bordeaux, as postulated by беһалдег (18), could be 
considered a factor of importance in this case. 
The results in the laboratory suggest, further, that the ratio 
of sprayed to unsprayed will vary considerably with the con- 
ditions. Before removing the potometers to the laboratory, 
the night temperatures were so low that two night “runs” 
(ineluding the interval from about 6 Р.М. to 8 А.М.) were 
necessarily excluded on account of leakage. Other night “гип,” 
as shown in the tables, indicate the probability that under 
certain conditions unfavorable for evaporation, the surface 
